Conventional methods for measuring residual stress are classified into destructive and non-destructive types dependent on the destruction of estimated materials. There needs to introduce non-destructive type for estimating residual stress for structures or facilities under construction or in service because it's impossible for them to apply to destructive type.
Conventional methods for measuring residual stress are described that repeatedly measure variation of an indention depth according to continuous indentation of the indenter on the surface of samples and calculate the residual stress based on the measured results such as the indentation load and depth.
For example, there are described “Apparatus for determining residual stress, method for determining residual stress data using it, residual stress determining method using it and recording medium thereof” in Korean patent No. 0416723 and “Estimating method of residual stress using continuous indentation” in Korean patent No. 0517857.